Which drugs are safe to take for a woman while she is pregnant? If a woman becomes pregnant while on therapy is there a risk to the fetus? If a woman is pregnant, which drugs increase the risk of birth defects? To help guide medical providers and patients, the Food and Drug Administration (FDA) has established certain categories that for the most part define what is safe and what is not safe. But there are gray areas within most of the categories. This is why it is so important to seek medical advice—medical providers base decisions on a variety of factors, such as does the risk outweigh the benefit, personal experience using a certain drug and the latest medical research.